<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        header{
            width: 100%;
        }
        footer{
            width: 100%;
        }
    </style>
</head>
<body>
 

    <header>
        <h3>html5新增语义化标签</h3>
        <p>header头部标签</p>
        <p>nav导航标签</p>
        <p>article内容标签</p>
        <p>section定义文档某个区域</p>
        <p>aside侧边栏标签</p>
        <p>footer尾部标签</p>
    </header>

    <footer>

    </footer>
</body>
</html>